Telephone system



Nov. 15, 1938. R, F. MAssoNNr-:AU 2,136,530

K- TELEPHONE SYSTEM Filed Aug. 13, 1935 T0 SUCCESS/VE Gl T REGISTERS NVENTOR 'Q'.FMASSNNEAU A TTORNEY Patented Nov. 15, 1938 PATENT OFFICE TELEPHONE SYSTEM Robert F. Massonneau, to Bell Telephone New York, N. Y.

Application August 13,

5 Claims.

This invention relates to signaling systems and more particularly to dial control systems in which impulses are produced at one end of a line for transmission to the other end. My invention is 6 specifically directed to the control of an alternating current generator by an impulse dial So that the rotation of the dial back to normal from any digit aperture brought into coincidence with the finger stop,' will rotate the armature oi' l the generator to produce a number of alternating current sine waves which is lthe product of the value of the digit and that of some constant.

A further feature'of this invention is the use of an inductor motor relay, described and claimed in my copending application Serial No. 6,787, as a registering device of the groups of alternating current impulses generated by the dial controlled alternator.

As is well known, electrical impulses are usually Jproduced by momentary interruptions of the r pulsing range to limits determined by the electrical characteristics of the line which very often produce pulse distortion that adversely affects the pulse receiving equipment. Further, direct current pulsing is also limited to the ohmic resistance oi' the line so that, when said. line is very long, repeaters have to be interposed at suit-1 able distances along its length to amplify, or re- 30 produce, the pulses to aiect the pulse receiving equipment at the distant end.

By means oi' my invention, that is, by the use oi' an alternating current generator as an impulse producer, the tended, the physical characteristics of the pulses are practically undistorted by the line constants and the use of impulse repeaters greatly reduced.

A clearer understanding of the scope and purpose of the invention may be obtained from the following description taken in connection with the accompanying drawing which shows, at one end of a line, 'a telephone subscribers station I with an inductor alternator i0 whose armature 2 is rotatably geared to a calling dial 3. At the other end of said line there is an alternating pulse receiving arrangement which comprises a thermionic detector 4 having its grid connected to the tip conductor 5 of the line and itsv plate to a terminal of the primary winding P ol transformer '1; the other terminal of said primary Winding being connected to a grounded source of battery. The secondary S of said transformer is bridged between the winding of the register ad- Vance relay 8 and the iield winding 9 o; the 1nansmission line. This necearlly reduces the.

pulsing range is greatly ex- New York, N. Y., assignor Laboratories, Incorporated, a corporation oi' New York 1935, serial No. 35,909

ductor motor switch, described and claimed in my above-mentioned cpending application.

The inductor alternator l 0 may be of any sultable type, but I prefer to illustrate the operation of my invention with one having a rotatable ard mature 2 of the squirrel cage type whose shaft carries a gear I2 with teeth meshing with those of a second gear I3 intermediate gear l2 and the ratchet wheel I4, both of which are rigidly mounted on the dial shaft 2t while the dial wheel 3 l0 is rotatably mounted thereon. A spring i6 is connected to the frame of the dial and to the dial wheel, which spring is wound up when the Wheel is rotated in a clockwise direction so that i the energy stored in the spring during such an operation will cause the wheel, when released, to restore to its normal condition. 0n the inner surface of the front piste of the dial Wheel d, pawl i5 is mounted to engage the notched sur faces of the ratchet Wheel i4, being firmly held in position Within a notch by spring 25, which at one end is attached to the dial plate and the other end to theu free end of the pawl. During the time when the dial Wheel 3 is being rotated, to a position Where any one of the digit apertures is directly above the flnger stop 2t, pawl l5 slides over the'teeth of the ratchet it and comes into engagement with one of the notches at the stop position of the dial wheel. When the Wheel is up, `the tension stored in the spring will cause said Wheel to rotate back to its normal position in a counter-clockwise direction. During this rotation, pawl l5 rotates ratchet i4 and inasmuch as said ratchet is rigidly ixed to the shaft 2B which carries the gear I3, said gear moves with the shaft, rotating gear l2 and armature 2,. The ratio of the two gears l2 and i3 shall be such l that for each return to normal of the dial from the position to which it may have been pulled from one oi' the finger apertures, there shall be a 40 number of revolutions of the armature 2 equal in number to the product of the digit indicated in the finger aperture brought into position above the linger stop 23 when the dial wheel is let go and a suitable constant which can be used with each of the digits in the other digit apertures. Thus, if the constant is l0, and the dial wheel is rotated so that the finger aperture which'has the digit i is just above the ringer stop 23 and then released, the armature 2 will make ten rev- 50 olutions. Since the amature, in rotating, cuts across a magnetic field established through the stator I1, ten sinusoidal current waves will be generated in the line circuit, as explained hereinafter. If,lri the same way, digit 6 is dialed, the 55 armature will revolve sixty times and sixty sinusoidal current waves will be produced in the line.

will now describe the operating detaiis of my invention. When the subscriber at substation I removes his receiver from the hook to initiate a call, the line is extended to an impulse register in the ordinary way well known to the automatic telephone art, As a result, a circuit is completed between the register and the subscribers line cpmprising, for example, the grounded battery through line relay Ii, conductor 5, through the subscribers subset, the field winding of stator Il, conductor G to ground. Line relay ii operates to close its contacts, which are eective to operate such parts oi the register as control the transmission (not shown) of dial tone to the calling station as an indication that he may proceed to dial. The circuit above described is further eiective in producing lines or" force in the iield magnets of the alternator iii, which lines of force will be cut by the conductors of the armature 2 when said armature rotates under the inuence of the dial as above described.

The subscriber now pulls the dial around to the nger stop 23 from any digit aperture and, in so doing, winds up the spring E6. In the movement oi' the dial wheel, ratchet wheel i4 is uninfiuenced, but pawl I5 slides over the teeth of said ratchet wheel. When the bottom of the finger aperture cornes into coincidence with the top of the nger stop 23, pawl I5 rests in the notch between two successive teeth. When the dial is released, the energy stored in the spring I6 by the clockwise rotation of the dial wheel inrluences said dial wheel to return to its normal position. Ratchet wheel I4 and gear I3, however, are both rigidly xed to shaft 24, and since pawl I5 is wedged in the notch of ratchet wheel I4 to which it was advanced, the return movement oi the dial wheel will cause the pawl to push the axis assembly of ratchet wheel I4 and gear I3 in a counterclockwise rotation. Inasmuch as gear I3 is meshed with gear i2, and since the ratio between the teeth of these gears is such that for an arcuate displacement of the dial wheel from its normal position to any digit aperture above the nger stop 23, armature 2 will make as many revolutions as the product of the value of the digit designated by the aperture and a constant, it follows that when the dial wheel is rotated to the finger stop position for any digit, said armature 2, on the return of the wheel to normal, will make that many revolutions. With each revolution of the armature, a sinusoidal current wave is generated in the line circuit by the conductors of the armature 2 cutting the lines of force generated by the steady current traversing the generator stator I'I, so that there will be as many sinusoidal current waves produced as complete revolutions of the armature.

At the terminating end, the instantaneous value of each sinusoidal current wave serves to alter the potential on the grid of the thermionio device G, causing thereby a plate current of proportionate intensity to pass through the plate circuit including the primary Winding `(P) of the 'transformer l. A current is further induced in the secondary winding S in the circuit which includes the field winding I8 of the motor relay 9, completely described in my above-mentioned copending application, and the .winding of the register advance relay 8 in parallel therewith, causing said relay to operate and hold so long as current flows through the secondary circuit.

So long as the sinusoidal alternating currents aisacso are being produced in the line in rapid succession bythe continuous rotation of the generator armature 2, the potential of the grid of the detector 4 will continue to be altered correspondingly and cause a flow of current in the plate circuit and an induced alternating current in the secondary circuit (S) of the transformer 1 which will produce. an alternating iield of proportionate intensity in the stator of the motor relay 9. As a result, armature I9, which is of the squirrel cage type, as described in my above-mentioned copending application, rotates in a counter-clockwise direction and influences gear 2E to step brush 2i over the terminals of its cooperating contact arc, said brush advancing over as many terminals as the number dialed.

When the dial has returned to normal and the potential on the line is restored to the steady current condition, the potential of the grid is reduced, the plate current ceases, and no alternatf ing current is induced in the secondary circuit, whereupon relay 8 releases to control the operation of switches or equivalent structures (not shown) that willadvance the conductors on the terminals of the arc accessible to brush 2I to a succeeding register in the manner well known in the telephone switching art. Brush 2i, in the meanwhile, is returned to normal through gear 20'by virtue of the energy that was stored in spring 22 when gear 20 rotated under the infiuence of armature I9.

When the subscriber dials the second digit, the above operations are repeated, and since the terminals of the arc associated with brush 2l are now advanced to another register, the second digit will be registered thereon in accordance to the terminal to which brush 2l will be advanced.

What is claimed is:

1. A signaling system comprising a dial movable from its normal position in accordance with different digital values, means for returning said dial to normal, an alternator and means responsive to the movement of said dial for controlling said alternator to produce a number of alternating current sine waves proportional to the movement oi' said dial.

2. A signaling system comprising a dial movable from its normal position in accordance with different digital values, means for returning said dial to normal, an alternator, means responsive to f the movement of said dial for controlling said alternator to produce a number of alternating current impulses proportional to the movement of said dial, a stepping device, and means responsive to said alternating current impulses for operating said stepping device a number of steps equal to the number of impulses.

3. A signaling system comprising a dial movable from its normal position in accordance with different digital values, means for returning said dial to normal, an alternator, means responsive to the movement of said dial for controlling said alternator to produce a number of alternating current impulses proportional to the movement of said dial, a switching device, and means responsive to said alternating current impulses for operating said switching device for a period of time equal to that of all the impulses.

4. A signaling system comprising a dial movable from its normal position in accordance with diierent digital values, means for returning said dial to normal, means responsive to the return movement of said dial for producing a current of equal duration to the duration of said return movement and stepping means responsive to said current for measuring the amount of said displacement.

5, A signaling system comprising a dial movable from its normal position in accordance with different digital values, means for returning said dial to normal, an alternator, means responsive to the movement of said dial for controlling the operation of said alternator to produce a number of alternating current impulses proportional to the movement of said dial, a thermionic detector responsive to said impulses, a stepping device responsive to alternating current, and means responsive to the operation'of said thermionic detector for operating said stepping device a number of steps equal to the number of impulses.

ROBERT F. MASSONNEAU. 

